NOTE: I plan on getting a new, stronger filter very soon - when I originally bought the tank, I did not know much about GPH. However, I am due to change my filter media and I have a couple of questions. I currently have a 20g high with a Tetra Whisper EX30 HOB. I already know all about the importance of beneficial bacteria, but I was reading some of the other threads and I've seen people say that they cut off pieces of the old media and put it in the filter with their new cartridge. Is there a certain way to do this? Do I just cut off any piece of it, how big should it be, and where exactly should I place it inside of the filter housing? Also, if I am using this method, how often should I be changing the cartridge - I've seen a lot of conflicting opinions on this. Thanks in advance; I appreciate it!